i. Technical Field
This invention pertains generally to the field of roll-winding apparatus, and pertains more particularly to a high torque drive mechanism useful in paper web winders.
ii. Prior Art
Roll-winding devices are used in various industries for winding web-like material. In the paper industry, such devices are commonly used in connection with roll-slitting machines, in which a roll of paper the width of a paper machine is divided into several narrower rolls by unfeeling the paper from the wide supply roll, cutting the paper web longitudinally, and rewinding the resulting individual, narrower webs into narrower rolls. The longitudinally separated strips or narrow webs are passed around one or two winding rollers, and are individually attached to winding tubes or cores, the lengths of which correspond to the width of the individual strips concerned. The ends of the winding tubes are held in clamping heads, which are located at the upper ends of carrier arms. The clamping heads are driven, and rotate the winding tubes to form the individual narrower rolls from the narrow strips supplied thereto. The narrow rolls can be reeled in such a way that, as they are being wound, the rolls are pressed against the winding rollers with adjustable compressive force; or the rolls can be reeled freely, i.e. , leaving an interval or space between the winding roller and the roll being wound.
As the diameter of the forming roll increases, the carrier arms, the lower ends of which are pivotably mounted on horizontal axes parallel to the winding axis, move away from the winding rollers.
From both theory and practice in the reeling of rolls, it is known that, in order to achieve a well-reeled structure, it is necessary to have the greatest possible center moment. This is especially true for rolls which are large in both diameter and width, i.e., heavy rolls; and for rolls which are formed by so-called free reeling, in which the width of material can be applied over only one central moment per winding station.
The use of hydraulic drives on the carrier arms to rotate the rolls being wound is known. Hydraulic drives provide adequate performance for rolls of certain dimensions. Nevertheless, hydraulic drives are not favored for use in paper winding applications, since there is practically no such thing as a leakproof hydraulic system. The danger always exists that the hydraulic oil will find its way onto the paper, which can lead to extensive product rejection.
The use of electric drives for roll winding devices is also known, and has been favored for its clean operation compared to hydraulic drives, particularly for winding smaller rolls, and lighter materials. In order to achieve the required torque necessary for winding larger rolls and heavy materials such as paper, it has heretofore been necessary to use very large electric motors. The motors are mounted on the outsides of the carrier arms, and, due to the motor overhang, the motor precludes the reeling of rolls narrower than about seven-hundred millimeters (700 mm), since the carrier arms of a roll can not be brought any closer together because of the motors. Nevertheless, it is often desirable to reel rolls narrower than seven-hundred millimeters (700 mm).